The authors' thesis establishes that the administrative authorities' action of regulation, inspection, surveillance and control has changed to be the application of a administrative law to the development of a economic administrative law, open to the canalization of information derived from market process and the agreement between authorities and regulated industries interested or affected by regulation. The authors center their views in the development of three aspects of public intervention in economy: first, they study the role of State intervention in economic activities; second, they analyze the principle of legality or the rule of law and its application to administrative action; third, the authors study the relation between state intervention in economy under the rule of law, and the economic regulation as an instrument of public administrative intervention in economy. These three aspects permit them to explain their thesis referred to the concept of regulation and its task in economic the economic intervention process, contrasting their opinions with the traditional thesis that justifies the State's intervention in economy pointed to the need of correction of market failure.